阻力平衡器在除尘管网中的应用

通过对在除尘系统中作为流体阻尼元件的阻力平衡器和调节阀门的对比分析,阐述了除尘管网中采用阻力平衡器的意义, 并对阻力平衡器的结构、工作原理和设计计算进行了介绍,最后强调了阻力平衡器使用时应注意的事项.     

交通运输网络可靠性研究分析

重点分析连通可靠性、出行时间可靠性、能力可靠性、行为可靠性和潜在可靠性等评价道路网络性能的指标,在回顾和总结交通网络可靠性研究发展的基础上,针对国内外的研究现状,提出了目前研究中存在的问题,描述了该领域有待研究的方向。     

多媒体远程实时控制系统

本文给出了多媒体远程实时控制系统的分层结构模型，介绍了基于该模型，实现网络实时传输和远程监控的关键技术和实现方法。为实现实时通信，减轻网络负载，系统可以根据当前的网络状态选择合适的协议来传输通信数据，引入多线程控制和协调机制，以实现并发控制。     

Field‐Scale Application of Three Types of Neural Networks to Predict Ground‐Water Levels1

Abstract: In this paper, a field‐scale applicability of three forms of artificial neural network algorithms in forecasting short‐term ground‐water levels at specific control points is presented. These algorithms are the feed‐forward back propagation (FFBP), radial basis networks (RBN), and generalized regression networks (GRN). Ground‐water level predictions from these algorithms are in turn to be used in an Optimized Regional Operations Plan that prescribes scheduled wellfield production for the coming four weeks. These models are up against each other for their accuracy of ground‐water level predictions on lead times ranging from a week to four weeks, ease of implementation, and execution times (mainly training time). In total, 208 networks of each of the three algorithms were developed for the study. It is shown that although learning algorithms have emerged as a viable solution at field scale much larger than previously studied, no single algorithm performs consistently better than others on all the criteria. On average, FFBP networks are 20 and 26%, respectively, more accurate than RBN and GRN in forecasting one week ahead water levels and this advantage drops to 5 and 9% accuracy in forecasting four weeks ahead water levels, whereas GRN posted a training time that is only 5% of the training time taken by that of FFBP networks. This may suggest that in field‐scale applications one may have to trade between the type of algorithm to be used and the degree to which a given objective is honored.     

基于C/S+B/S混合模式的城市重大危险源管理系统的研究

分析城市重大危险源管理系统的功能结构,针对现阶段技术应用的局限性,笔者提出C/S+B/S混合模式的解决方案;对数据库系统、网络构架及安全性、兼容性和模型系统等关键技术进行研究;开发出基于C/S+B/S混合模式的城市重大危险源管理系统。该系统对解决城市重大危险源统一管理与布局分散的矛盾,实现重大危险源动态监管和重大事故应急指挥智能化,提高事故应急救援指挥和救援行为的效率有重要意义。     

甘肃省冬春季人工增雨雪作业指挥系统

为了提高甘肃省人工增雨雪的水平和效果，准确、及时地把握作业气象条件，使人工增雨雪在抗旱减灾中取得更好的社会、经济效益，研制建立了“甘肃省冬春季人工增雨雪作业指挥系统”。该系统包括作业信息系统、作业指挥系统和效果检查系统共3个分系统。详细介绍了各分系统的组成和功能。     

Physical and Economic Sustainability of Water: New Approach Using the Case of the Big Lost River,Idaho

A new approach for evaluating water sustainability is introduced by comparing physical and economic sustainability. To achieve physical sustainability, water should be available in sufficient quantity and of good quality and used efficiently. The economic sustainability can be achieved by balancing between costs and values of water. The objectives of this study were to estimate the physical and economic sustainability of surface water in the Big Lost River, south–central Idaho. The study used a Bayesian network by building a graphical diagram of nodes representing all significant variables related with the sustainability, such as water demand, water quality, and the different costs and values of water. The study showed that the likelihood of the physical sustainability is less than that of the economic sustainability, which is attributed to the scarcity of water in the Big Lost River. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Specificity of Life Conditions for Commercial Invertebrates on Artificial Substrates in the Eutrophicated Amur Bay,the Sea of Japan

The consequences of anthropogenic impact on the water area of Amur Bay (the Sea of Japan) near Vladivostok include the eutrophication of coastal waters and littering with various objects used as artificial substrates, which protect sedentary animals from predators and contribute to the survival of their larvae. An indicator of eutrophication, the diatom Skeletonema costatum accounting for 81–96% of the total abundance of phytoplankton (Stonik and Selina, 1995), is consumed mainly by barnacles and the Pacific oyster. Thus, these animals gain an advantage in the colonization of artificial substrates. The results of the study suggest that eutrophication will lead to changes in the structure of the marine community.     

建筑物走廊型通道中火灾烟气流动特性的研究

应用网络模型方法,将建筑物走廊型通道合理地划分为多个节点,在火源为10kg木材的情况下,利用已开发成功的烟流性状预测软件对四川消防科研所的一座实体建筑物进行了模拟计算,获得了各节点烟流性状的发展变化规律。经比较,模型计算结果与实验数据十分符合。证明走廊型通道的多节点划分方法正确、预测软件实用可靠。根据烟气侵入走道中两节点的时间差及两节点间距,提出了烟气弥漫速度的计算方法。该算法与实测结果间的相对误差小于3%,实例应用及研究的成果,为建筑物火灾时安全疏散动态模拟研究提供了理论依据。     

基于小波神经网络的瓦斯涌出量预测研究

准确地预测瓦斯涌出量对于指导矿井设计和安全生产有重要意义,而瓦斯涌出量是一个与自然因素及开采技术等多因素有关的非线性建模问题。鉴于传统神经网络方法解决非线性问题收敛速度慢,易陷入局部最优解的缺陷,笔者提出一种既充分利用小波变换的时频局部化性质,又能结合神经网络的自学习能力的小波神经网络预测瓦斯涌出量的方法,并建立了预测模型。在此基础上,采用Delphi语言,设计了小波/BP神经网络仿真器。通过实例分析表明该方法较传统神经网络收敛迅速,预测精度高。